Flexible actuators, e.g. in the shape of bellows for performing straight axial movements are previously known. Bellows can only execute very limited movements and if the material of the bellows is rubber or the like it can only carry relatively low pressures.
In case larger axial movements are to be performed, for example one or several meters long, and under high pressure e.g. 200 bar or more, only piston-cylinders have up to now been used. If it however is also desired that the actuator should execute curved movements in one or several planes, piston-cylinders can not be used.